Massive eruption at Sinabung volcano, ash to 16.7 km (55 000 feet) a.s.l.

A high impact volcanic ash eruption started at Sinabung volcano, Indonesia at 01:53 UTC on Monday, February 19, 2018. Pyroclastic flows traveled 3.5 km (2.1 miles) and 4.9 km (3 miles) from the summit. Ash plume was reaching an altitude of 16.7 km (55 000 feet) above sea level, the Darwin VAAC reported 04:50 UTC. Aviation Color Code was raised from Orange to Red.

The eruption started at 01:53 UTC (08:53 local time) and lasted 4 minutes and 51 seconds, Sinabung Volcano Observatory reported.

Their best estimate of the ash cloud top at 02:13 UTC was 7.4 km (23 872 feet) above sea level. The observatory noted that the ash cloud is drifting to the east and southeast, adding that its top may be higher than what can be clearly observed from the ground. The Aviation Color Code was raised from Orange to Red.

"Pyroclastic flow is observed through the ESE slope to a distance of 3.5 km [2.1 miles] from the summit and through the south slope to a distance of 4.9 km [3 miles] from the summit," they said.

Major ashfall was reported around the volcano and visibility was down to only 5 to 10 meters (16 – 32 feet).

The volcanic ash cloud is reaching an altitude of 16.7 km (55 000 feet) above sea level and extending 46.3 km (28.7 miles) ENE, the Darwin VAAC reported 03:35 UTC. At the same time, the second volcanic ash cloud was reaching 7.6 km (25 000 feet) a.s.l. and extending 18.5 km (11.5 miles) S. 

At 04:53 UTC, the Darwin VAAC said that one volcanic ash cloud was observed reaching an altitude of 13.7 km (45 000 feet) at 04:50 UTC and extending 138.9 km (86.3 miles) to the northwest, while the second volcanic ash cloud was reaching 6.7 km (22 000 feet) and extending 46.3 km (28.7 miles) to the south.

"High impact volcanic eruption is clearly observed on satellite imagery," they noted, adding that the 04:50 UTC volcanic ash cloud heights were estimated based on plume top IR temperature and 00:00 UTC February 19 Medan sounding.

The National Disaster Mitigation Agency said there are no reports of fatalities and injuries.

Sinabung's first eruption in known history took place in August 2010. It lasted about a month and had Volcanic Explosivity Index of 2.

Seismicity fluctuated until September 2013, when dense white plumes started rising 100 to 150 m (328 to 492 feet) above the crater.

Sinabung's first major eruption in known history occurred on September 17, 2013 and the volcano remains active ever since. Tens of thousands have been evacuated.

Between February 2014 and May 2016, eruptions at Mount Sinabung claimed lives of 23 people.

Geological summary

Gunung Sinabung is a Pleistocene-to-Holocene stratovolcano with many lava flows on its flanks. The migration of summit vents along a N-S line gives the summit crater complex an elongated form. The youngest crater of this conical, 2 460-m-high (8 070 feet) andesitic-to-dacitic volcano is at the southern end of the four overlapping summit craters.

An unconfirmed eruption was noted in 1881, and solfataric activity was seen at the summit and upper flanks in 1912.

No confirmed historical eruptions were recorded prior to explosive eruptions during August – September 2010 that produced ash plumes to 5 km (16 404 feet) above the summit. (GVP)

Featured image: Eruption of Mount Sinabung on February 19, 2018. Credit: Polres Tanah Karo, Kabanjahe